484 research outputs found

    К палеоантропологии средневекового населения Поволжья

    Get PDF
    Physical appearance of the population of the Golden Horde resulted from interbreeding of representatives of two big races, i.e. the Mongoloid and the Caucasoid. The presence of the Mongoloid component is to some extent manifested in the appearance of inhabitants of all the Golden Horde towns. Nevertheless, it is the Caucasoid features that prevailed in urban population

    Постстресові зміни нейро-ендокринного статусу та метаболізму у щурів з різними типами початкового вегетативного гомеостазу, індукованими біоактивною водою Нафтуся

    Get PDF
    Установлено, что выявленные ранее амбивалентные (ваго- и симпато-тонические) эффекты биоактивной воды Нафтуся на вегетативный гомеостаз крыс существенно и различным образом влияют на пост-стрессовую вегетативную и гормональную регуляцию, ферментемию, а также обмен электролитов и липидов.Is established, that revealed earlier ambivalence (vago- and sympathototonic) effects of bioactive water Naftussya on vegetative homeostase at rats it is essential also by various image influence on poststressory vegetative and hormonal regulation, fermentemia, and also exchange of electrolytes and lipids

    Accrual-based and real earnings management and political connections

    Get PDF
    This study examines whether the trade-off between real and accrual-based management strategies differs between firms with and without political connections. We argue that politically connected firms are more likely to substitute real earnings management for accrual-based earnings management than non-connected firms. Although real earnings management is more costly, we expect that politically connected firms prefer this strategy because of its higher secrecy and potential to mask political favors. Using a unique panel data set of 5493 publicly traded firms in 30 countries, our results show that politically connected firms are more likely to substitute real earnings management strategies for accrual-based earnings management strategies than non-connected firms. We also find that when public monitoring and, therefore, the risk of detection increases, politically connected firms are more likely to resort to less detectable real earnings management strategies. Our finding that political connections play a significant role in the choice between accrual-based and real earnings management strategies suggests that focusing only on accrual-based measurements underestimates the total earnings management activities of politically connected firms

    Refining data–data and data–model vegetation comparisons using the Earth mover's distance (EMD)

    Get PDF
    Comparing temporal and spatial vegetation changes between reconstructions or between reconstructions and model simulations requires carefully selecting an appropriate evaluation metric. A common way of comparing reconstructed and simulated vegetation changes involves measuring the agreement between pollen- or model-derived unary vegetation estimates, such as the biome or plant functional type (PFT) with the highest affinity scores. While this approach based on summarising the vegetation signal into unary vegetation estimates performs well in general, it overlooks the details of the underlying vegetation structure. However, this underlying data structure can influence conclusions since minor variations in pollen percentages modify which biome or PFT has the highest affinity score (i.e. modify the unary vegetation estimate). To overcome this limitation, we propose using the Earth mover's distance (EMD) to quantify the mismatch between vegetation distributions such as biome or PFT affinity scores. The EMD circumvents the issue of summarising the data into unary biome or PFT estimates by considering the entire range of biome or PFT affinity scores to calculate a distance between the compared entities. In addition, each type of mismatch can be given a specific weight to account for case-specific ecological distances or, said differently, to account for the fact that reconstructing a temperate forest instead of a boreal forest is ecologically more coherent than reconstructing a temperate forest instead of a desert. We also introduce two EMD-based statistical tests that determine (1) if the similarity of two samples is significantly better than a random association given a particular context and (2) if the pairing between two datasets is better than might be expected by chance. To illustrate the potential and the advantages of the EMD as well as the tests in vegetation comparison studies, we reproduce different case studies based on previously published simulated and reconstructed biome changes for Europe and capitalise on the advantages of the EMD to refine the interpretations of past vegetation changes by highlighting that flickering unary estimates, which give an impression of high vegetation instability, can correspond to gradual vegetation changes with low EMD values between contiguous samples (case study 1). We also reproduce data–model comparisons for five specific time slices to identify those that are statistically more robust than a random agreement while accounting for the underlying vegetation structure of each pollen sample (case study 2). The EMD and the statistical tests are included in the paleotools R package (https://github.com/mchevalier2/paleotools, last access: 3 May 2023).</p

    FlashCam: A fully digital camera for CTA telescopes

    Full text link
    The future Cherenkov Telescope Array (CTA) will consist of several tens of telescopes of different mirror sizes. CTA will provide next generation sensitivity to very high energy photons from few tens of GeV to >100 TeV. Several focal plane instrumentation options are currently being evaluated inside the CTA consortium. In this paper, the current status of the FlashCam prototyping project is described. FlashCam is based on a fully digital camera readout concept and features a clean separation between photon detector plane and signal digitization/triggering electronics.Comment: In Proceedings of the 2012 Heidelberg Symposium on High Energy Gamma-Ray Astronomy. All CTA contributions at arXiv:1211.184

    Calibration and performance of the photon sensor response of FACT -- The First G-APD Cherenkov telescope

    Full text link
    The First G-APD Cherenkov Telescope (FACT) is the first in-operation test of the performance of silicon photo detectors in Cherenkov Astronomy. For more than two years it is operated on La Palma, Canary Islands (Spain), for the purpose of long-term monitoring of astrophysical sources. For this, the performance of the photo detectors is crucial and therefore has been studied in great detail. Special care has been taken for their temperature and voltage dependence implementing a correction method to keep their properties stable. Several measurements have been carried out to monitor the performance. The measurements and their results are shown, demonstrating the stability of the gain below the percent level. The resulting stability of the whole system is discussed, nicely demonstrating that silicon photo detectors are perfectly suited for the usage in Cherenkov telescopes, especially for long-term monitoring purpose

    FACT -- the First Cherenkov Telescope using a G-APD Camera for TeV Gamma-ray Astronomy (HEAD 2010)

    Get PDF
    Geiger-mode Avalanche Photodiodes (G-APD) bear the potential to significantly improve the sensitivity of Imaging Air Cherenkov Telescopes (IACT). We are currently building the First G-APD Cherenkov Telescope (FACT) by refurbishing an old IACT with a mirror area of 9.5 square meters and construct a new, fine pixelized camera using novel G-APDs. The main goal is to evaluate the performance of a complete system by observing very high energy gamma-rays from the Crab Nebula. This is an important field test to check the feasibility of G-APD-based cameras to replace at some time the PMT-based cameras of planned future IACTs like AGIS and CTA. In this article, we present the basic design of such a camera as well as some important details to be taken into account.Comment: Poster shown at HEAD 2010, Big Island, Hawaii, March 1-4, 201
    corecore